Class A Gift

You'll need to have a mechanic check the chassis and a RV tech check the house. There are a few specific items that will need to be checked that are difficult to find without a bit of experience, such as water leaks and sidewall delamination. In the mean time if you have power and water available I would do a bit of weekend driveway camping which will give you opportunity to check out the various house side items such as the water heater, HVAC, entertainment systems,,,.

Did the prior owner have service records? If not you will have to presume that the various power train and generator fluids are all in need of changing.

One thing you can do is check yourself now are the tire date codes and air pressures. Doesn't require expert knowledge and there is a lot of internet info on it that a search engine will find. Maybe even too much. Limit road time until you can verify. A blow out can get real expensive beyond the cost of the tire.

See if you can get a Mobil RV mechanic to look it over for a reduced rate or as a donation to support your organization.
In turn give him some word of mouth advertising or one of his stickers on the back.
Even a local Freightliner shop might check out the chassis.
Personally I say sell it. The cost of up keep and ownership could be a huge drain on your organization.